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Status of Radiological Activity in Japan - FAQ

Background

  • A massive earthquake hit Japan and triggered an enormous tsunami on March 11th, 2011.
  • Nuclear reactors in Fukushima Daiichi power plant were damaged by the event.
  • There is a massive ongoing effort to bring the reactors under control and the process is expected to last for several more months.
  • Major national and international organizations relevant to nuclear safety continue to follow the situation very closely.
  • The BCCDC is in regular contact with these organizations about the situation. 

Frequently Asked Questions



What is radiation and what is background radiation?

Radiation is energy that is transmitted in the form of waves or streams of particles. It is present everywhere in our environment. There are two types of radiation: ionizing and non-ionizing.  

  • Ionizing radiation includes the radiation that comes from both natural and man-made radioactive materials such as cosmic rays, nuclear power plants and x-ray machines.
  • Non-ionizing radiation is a lower energy radiation such as radio waves, ultraviolet rays, microwaves and sunlight.  

Background radiation is the amount of ionizing radiation that exists in our environment or that we are exposed to from natural sources. This can vary in different parts of BC, for example it is higher at higher altitude and where there are deposits in the earth of radioactive minerals. On average in BC the dose we receive from background radiation every year is about 2-3 milli-Sieverts. Sieverts (Sv) are a unit of energy that is used to measure absorbed radiation. A milliSv is one-thousandth of a Sv. To put this in context the dose one receives from a return flight from Vancouver-Toronto is 0.01 milliSv; the dose from a dental x-ray is about 0.015 milliSv; the dose from a chest x-ray is 0.075 milliSv and the dose from a CT scan is 2-10 milliSv.  

Longer term atmospheric modeling looking at possible impacts on BC from the nuclear situation in Japan indicate that even if the scenario in Japan was significantly worse than it is now, any resulting radioactive contamination that reaches BC would be at concentrations so low that it is difficult to measure without extremely sensitive equipment. This is a thousandth or even less than normal background radiation levels from natural sources.

What is being done to monitor radiation in food and the environment that might be coming across the Pacific from Japan?  

The Canadian Albacore Tuna Association has monitored levels of radioactivity in their products from 2010, the year before the Fukushima (Japan) reactor incident and up to the present.  Both stored product from 2010, and fresh product since the 2011 episode were tested for Iodine-131, Cesium-134 and Cesium-137, three of the main radioactive isotopes released during the reactor incident. No samples had detectable levels of the radioactive Iodine or Cesium isotopes.

Canadian action levels for radioactivity in foods in situations of nuclear emergency (such as Fukushima) have been defined in Health Canada’s Guidelines for 3 food groups: fresh liquid milk, public drinking water, other commercial foods and beverages. The action levels are based on a dose of 1 milliSievert (mSv) accumulated during a nuclear emergency. To put this into perspective, 1 mSv is equivalent to one third (⅓) of the dose each individual receives annually from natural radiation. It is also about 2 to 5% of a dose due to an abdominal CT examination in radiology.  Radioactivity in milk, water and food samples is measured in units of Becquerels (Bq); depending on a person’s age and the type of radionuclide they may be exposed to, ingesting 1 Bq of radioactive material is equivalent to an internal radiation dose to the body between 1/100,000 and 2/100,000 (0.00001 to 0.00002) of a mSv.

The laboratory limit of detection for the fish samples tested was 0.002 Bq/g.  All samples tested had less than 0.002 Bq/g of Iodine 131, Cesium 134 and Cesium 137.  One kg (2.12 lbs.) of fish at the laboratory limit of detection would be equivalent to less than 2 Becquerels, or to a dose between 0.00002 and 0.00004 mSv. View the Canadian Albacore Tuna Association Report 2013 here or check them out on their Facebook page.

The Canadian Food Inspection Agency (CFIA) implemented enhanced import controls, which did/does not allow food and animal feed products from affected areas in Japan to enter Canada without acceptable documentation or test results verifying their safety. The results of all the testing, with the exception of the fish testing in February 2012, can be found here.

The Consumer and Clinical Radiation Protection Bureau of Health Canada uses a series of sensitive detectors to maintain permanent surveillance of radiation dose levels on Canada’s west coast and across Canada. Health Canada is adding to its existing monitors in BC to gather more detailed information on radiation levels in the province. BCCDC will be working with Health Canada to interpret the monitor readings. We do not expect that the monitors will show increases in radioactivity at levels of concern to health.

What does “cold shutdown” of the reactors mean? Is it important?

Cold shutdown of the reactors means that the reactor is brought down to a very low power and all residual heat generated by radioactive elements inside the nuclear fuel rods is dissipated continuously by means of a cooling system. After cold shutdown, it is possible to dismantle and decommission the nuclear reactors.

There is a story on the internet about emissions from Fukushima being responsible for increased infant mortality on the west coast of the United States. Is it true?

This story is not credible.  The BCCDC has confirmed that its authors analyzed and presented infant mortality statistics in a misleading and irresponsible way.  Please see this document for our own analyses of infant mortality in the US and in BC.  Although the story was not credible the BCCDC remains vigilant about monitoring the situation at Fukushima and assessing possible impacts on the health of the BC population.

► The Japanese Nuclear and Industrial Safety Agency (NISA) elevated the rating for the nuclear incident at the Fukushima plant to 7 on the INES scale. What does this mean?

The Japanese authorities made the decision to provisionally elevate the incident rating for reactors 1, 2 and 3 on the basis of the radioactivity levels they measured on the nuclear plant site and several kilometers around it. In addition, this provisional step will substantially help increase the level of emergency response by authorities.

Does the rating elevation mean that need to re-evaluate the radiation risk in BC?

No, the risk appreciation in BC depends solely on the real radiation levels present in our environment, and not on the Japanese rating. Since the first day of the nuclear incident in Japan, radiation levels in air have been continuously monitored by Health Canada to determine the radiological impact in BC and the rest of Canada. Similar monitoring investigations have been implemented along the US West Coast.

In addition to the continuous monitoring by Health Canada, samples of rainwater, seaweed, drinking water, and milk have been tested by different Canadian Agencies and institutions. The results of the tests have shown that insignificant traces of radioactivity were present a few days after the incident, notably during the last week of March. However, the more recent results in April indicate the absence of measurable quantities of radioactivity.

As stated on several occasions, BCCDC will continue to follow the Japanese nuclear situation until all reactors are brought to cold shutdown.

There was a new earthquake of magnitude 6.6 in Japan on April 11. Do we need to worry about another possible release of radioactivity from the nuclear reactors?

No, there was no new release of radioactivity to the atmosphere. Aftershocks were expected to occur in Japan. According to the Japanese authorities the off-site power of the nuclear plant went down for a short period, but was reinstated 50 minutes later.

I heard that drinking water and locally produced milk have been tested for radioactivity. Do we know what the results of the tests are?

Yes, a number of tests have been conducted by various agencies. All results show that the concentration levels in both water and milk were insignificant, at background level:                  

Trace amounts of radiation from the Fukushima nuclear power plant in Japan have been recorded in milk in Spokane, Washington. Should British Columbians be concerned about radiation in milk here?

British Columbians should not be concerned about radiation in milk or in any other British Columbian food products. The levels of radio-iodine that have been measured in Washington State are extremely low.  While such traces do show that we need to monitor BC produced foods for traces of dilute radioactivity coming from Japan, the measurements are far below internationally accepted levels of concern.

There have been Plutonium traces found in Japan few miles from the reactor. Is this a cause for concern in BC?

No. While plutonium can leak from a damaged reactor, it does not travel far from its point of release. Also, the traces found in Japan are not at levels that are serious enough to harm human health.

Researchers at Simon Fraser University have reported finding radioactive Iodine (I-131) from the nuclear reactor incident in Japan in rainwater and seaweed here in BC. Should I be concerned?

No, it was expected that minute amounts of radioactivity from the Japanese nuclear reactor incident would reach BC. The scientists at SFU used extremely sensitive equipment to find trace amounts of radioactive iodine. The amounts they found are less than one millionth the amount that has been shown to cause disease in the thyroid so there are no health concerns for people who drink rainwater or who eat seaweed here in BC. For example to reach a concerning level in the thyroid a person would have to drink 815,143 litres of water at one time. This radioactive iodine will continue to decay but we would expect that trace amounts may be found until several weeks after the nuclear reactor incident has resolved.

Should I stop drinking rainwater and eating seaweed?

No, there is no health concern from the minute amounts of radioactive iodine detected.

Do I need to take potassium iodide (KI)?

No, the amounts detected are much smaller than the amounts that would cause any concern with the thyroid gland and taking KI is not necessary and may be harmful.

Why did the radiation monitors that Health Canada operates not find I-131 in the air?

Some of the very sensitive radiation monitors in BC did detect radioactive iodine in very, very minute amounts. Because the total amounts were so small and within background radiation levels these were not reported separately. This was again expected and the trace amounts of radioactivity from Japan found by the very sensitive monitors are not a health risk to anyone in BC.


I heard on the news today that there was a highly radioactive water leak at one of the reactors and that workers were injured. Should I be concerned? 


No, there is no need to be concerned that this leak will impact us here in B.C. Japanese authorities have reported a water leak at Reactor #3 – water is leaking from the reactor vessel into the basement of the facility. This leak is within the reactor facility and is contained – it has not spread into the environment. It is very concerning for the workers in that building, as several people were exposed to high levels of beta particles, causing skin burns.The modelling that has been done by the Radiation Protection Branch of Health Canada has taken “worst case” scenarios into consideration. Even if a catastrophic reactor failure were to occur, any radiation that might reach B.C. would be very small and would not pose a health risk to people here in British Columbia.

I heard that radioactivity has been detected in some foods in Japan. Should I be worried?

Canada imports some fruits and vegetables from Japan but none from near the Fukushima nuclear site. While Iodine-131 and other radionuclides have been detected in some foods around Fukushima, these affected products are not exported to Canada as per Canadian restrictions on imported foods from Japan. The Canadian Food Inspection Agency (CFIA) is monitoring all Japanese food imports and the BC Centre for Disease Control works with them to interpret the information for the health of British Columbians. Any products currently on store shelves are not affected by the events in Japan.

Do I need to be concerned about radiation from people returning from Japan? I heard that some people arriving from Japan in the US set off radiation monitors.

There is no need to be concerned about people returning from Japan at this time. There is no information that suggests that people returning to Canada from Japan or other areas of Asia would have received contamination resulting from the current nuclear situation in that country. People in Japan should follow the advice of Japanese authorities and not enter the evacuation zones around the nuclear facilities.

While some low level of radiation was detected in a few people who were on flights from Japan that landed in the US, this was very minor and was not a health concern. Radiation detectors can measure very low levels of radiation that can result from natural sources (such as soil) or from people who have had a recent medical procedure (like scans or dye tests). There is no risk to others or to the individual from this low level of radiation and it is not felt to be related to radiation from the nuclear plant incident in Japan.

Should I be worried about the radiation that was detected in California?  

No, the monitors used are extremely sensitive and can detect infinitesimally small increases in radiation. It is not surprising given the time and wind patterns that this small increase was detected in California. This increase is the same as we would expect from a rainfall for example which causes a rise in background levels of radiation normally. It is far below any level that would have effects on human health and is not a concern. The detectors in BC, Washington State and Alaska have not shown any increase over background radiation levels. 

 

Last Updated: April 8, 2014